<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>自适应布局</title>
    <style>
        html,body{
            height: 100%;
        }
        body{
            margin: 0;
            padding: 15px;
            box-sizing: border-box;
            display: flex;
            flex-direction: column;
        }
        header{
            height: 80px;
            margin-bottom: 15px;
            border: 1px solid #080;
            padding: 20px;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        .input{
            align-self: flex-end;
        }
        .main{
            flex: 1;
            display: flex;
        }
        footer{
            border: 1px solid #000;
            text-align: center;
            margin-top: 15px;
        }
        .main>.aside{
            width: 200px;
            margin-left: 20px;
        }
        .main>.aside>div{
            border: 1px solid red;
        }
        .main>.content{
            flex: 1;
            border: 1px solid blue;
        }
    </style>
</head>
<body>
    <header>
        <img src="./logo.png" alt="logo" width="50px">
        <input class="input" type="text" placeholder="请输入用户名">
    </header>
    <div class="main">
        <div class="content">
            content
        </div>
        <div class="aside">
            <div>aside</div>
        </div>
    </div>
    <footer>
        footer
    </footer>
</body>
</html>